System and methodology for tracing to a source of unauthorized copying of prerecorded proprietary material, such as movies
US6285774A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 1998 |
| Grant date | Sep 4, 2001 |
| Priority date | — |
| Expiry date | Jun 8, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2005/91335
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
To enable the source of an unauthorized copy of an information-bearing medium, such as a video DVD, to be traced, a compressed digital signal stream to be stored on the medium is altered to include "running marks," that comprise pixel blocks changing in position frame by frame and encoded with information designating where and when the copy was made. The medium under test is played back synchronously with a reference medium containing the locations of the running marks together with original video. The source of copying message is advantageously encrypted and scrambled to avoid detection or alteration by a copyist. The message preferably is spread, for example into a spread spectrum carrier, to enhance discrimination among a large number of sources and enable demodulation in the presence of noise.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.